Japanese chess
棊 refers specifically to Japanese chess, a board game played with pieces on a grid.
棊 combines 木 (wood) with 其, which likely contributes the sound. The character originally referred to a wooden board game, specifically chess.
The top 其 looks like a game board with pieces, and the bottom 木 is wood. Picture a wooden chess board with pieces arranged on top.
For キ, imagine a key piece on the chess board: key -> キ, and moving that key piece decides the game.